Field of Invention
This invention relates to the field of pull-type farm implements and, more particularly, to a method and apparatus for tensioning conditioning rolls in a pull-type implement.
Description of Related Art
Self-propelled and pull-type conditioning mowers are used to cut and condition standing crop in a field. As crop material is severed from the field by either a rotary or sickle pull type mower conditioner, it passes through a pair of counter-rotating conditioning rolls before being returned to the ground either in the form of a windrow or swath. The conditioning rolls are typically ribbed and intermeshed with each other to crimp the stems of the crop material as they pass between the rollers.
The conditioning rolls of self-propelled conditioning mowers are often equipped with hydraulic roll tensioning mechanism which provides a controlled means to vary the amount of pressure applied to the conditioning rolls for improved drying characteristics such as illustrated in commonly-assigned U.S. Pat. No. 8,166,736 entitled Crop-Conditioning Apparatus Having Hydraulic Tension Mechanism. However, pull-type mower conditioners typically use springs to apply the necessary force on the conditioning rollers to condition the crop because many tractors lack the means to supply the necessary hydraulic pressure to the pull-type implement as some tractors only have enough hydraulic circuits available to operate primary functions. To change the amount of force on the conditioning rolls, adjustment of the springs is required, which can be labor intensive and time consuming. Additionally, due to the limitations of the springs, there are limitations to the amount of force that can be applied to the conditioning rolls.